Drilling apparatus and the like



DCC. l5, 1931. 1 H THULLEN 1,836,998

DRILLING APPARATUS AND THE LIKE Filed Nov.29, 1926. 4 sheets-Sheet 1 vwewboz a om 6MM" Dc. l5, 1931.'. l L, H THULLEN 1,836,998

DRILLING APPARATUS AND THE LIKE Filed Nov. 29 1926 4 Sheets-Sheet 2 llmllli .lmunnlilllll- Dec. 1s, 1931.

L. H. THULLEN D'RILLING APPARATUSND THE LIKE vFliedl Nov. 29 1926 4 Sheets--Sheetl 3 A y Z 17 jig 1 'l 7 Il f ze 5? 'Z8 i J4 il 75 69 l' Zaf' 4 la '.,7/

Patented Dec. 1,5, 1931 PATENT GFFICE LOUIS H. TH'ULLEN, 0F EAST ORANGE, NEW JERSEY- 'immature` APPARATUS AND TEE LIKE Application filed. November 29, 1926. Serial No. 151,305.

My invent-ion relates to improvements in drilling apparatus and the like and morel particularly vto an apparatus for drilling oil wells or earth boring apparatus, although e my invention may be used in many other and entirely different types of apparatus where it is desired to control the feed of a work member with respect to its work in accordance with the load imposed upon or resistance encountered by the Work member. The main object of the invention is to lprovide an arrangement in 'which the feeding of the drill or Work member with respect to its work is4 automatically controlled responsive to variations in the load imposed thereon or the resistance met thereby 4Wherebya more satisfactory and even and efficient operation of the apparatus is obtained.

Further and more specific objects, features and advantages will more clearly appear from the detail description given below taken in connection with the accompanying drawings which form a part of this specification.

ln the drawings, Fig., 1 is a View more or" i less diagrammatical illustrating certain portions of. an apparatus embodying my invention in one form. Fig. 2 is an elevation taken substantially on the line 2 2 of Fig.

1. Fig. 3 is a View similar to'Fig. 1 but 30 illustrating a modified form of apparatus.

method of conducting the operating Huid to and from the rotating apparatus. a section taken substantially on the line 5-5 of Fig. 3. Fig. 6 is a longitudinal section of parts shown in Fig. 5. Fig. 7 is a face view, partly in section, ofthe disc 11, cylinders 12 and part-s 13, 14 and 15 of. Fig. 1.

. Referring to Figs. l and 2, 6 represents a suitable steam engine ork other prime mover driving a sprocket Wheel 7 cooperating with a sprocket chain`8 driving a sprocket 9 keyed to the shaft 10' so that the engine Willv drive `the shaft 10.

a disc member 11 having rigidly secured thereto cylinders 1 2 containing suitable pistons and inlet valves 12al communicating with the outside atmosphere and outlet valves m `12b communicating with a passage in the Fig. 4 is a sectional detail illustrating onel Fig. 5 is On`one end -ofthe shaft .is

disc 11 described hereinafter. To the pistons are Apivotally connected piston rods 13 suitably connected with respect to a crank arm 14.on a shaft 15., The piston rods 13 'are pivotally connected'to their respective pistons in the cylinders 12 iii-'any Well known 55. or suitable manner, so that-if the disk 11 and cylinders 12 be held stationary and the shaft la rotated, the crank 14 Will operate vthe plston rods 13 to reciprocate their respective pistons in, the cylinders 12, Aand the pistons 60 will likewise be reciprocate' if the shaft 15 and crank 14 be held stationary-and the disk 11 and cylinders 12 be rotated With respect thereto. Likewise the pistons 4Will be reciprocated in their cylinders if the diskll be 65 rotated and the shaft 15 also be rotating, but at less speed than that of the disk 11. Suit able bearings are provided for shaft 1() as at 16 and suitable bearings are provided forshaft 15 as at 17. Mounted to rotate freely 70 on shaft 15 is a sprocket 18-which is adapted to be connected to be rotated by the shaft 15 by operation of a sliding clutch member 19. The sprocket 18 drives a sprocketchain 20 passing over a sprocket 21 on a shaft 22 75 which has secured thereto abevelled gear meshing with a bevelled gear 23 on the underneath side of a rotarytable member 24. The rotary table member 24 is so constructed as 'to provide a square aperture or hole 25 80 therein through `vvhichextends one section 26 of a drilling member, saidy section being square in cross-'section so as to substantially it the square 4opening 25 whereby rotation of the table 24 rotates the section 26 of the 85 drilling member. Suitably connected to the section 26 are vother sections 27 of -the v drilling member, `Which extend'into the hole or Well being'v drilled in the groundwhen the apparatus is lused, for example, for 90 drilling oil Wells.

28`represents another shaft `having bearings :1t-29. Secured lto and rotated by a'shaft. 28 is a' drum 30-on which is adapted to be*` Wound a rope or`cable 31. (see Fig. 2) which 95 cable passesaround pulleys 32 andl 33,v the latter being `connected by hook mechanism by. those skilled in the art, the top part 36` 100 of the drilling member being connected so as to raise and lower the otherv sections of the drilling member but remaining stationary with respect thereto as the latter is revolved or rotated by the table 24. A suitable water connection is shown at 37 through which water may be forced down the drilling member for purposes well understood by those skilled in the art.

The shaft 28 may be rotated at one speed by means of a sprocket 38 keyed to the shaft 10, operating the sprocket chain 39 passing over a sprocket 40 loose on theshaft 28 but adapted to be connected to rotate shaft 28 by clutch member 41. If it is desired to rotate the drum 30 from the shaft 1() but at a different speed, this may be accomplished by sprocket 42 keyed on the shaft 10, operating sprocket chain 43 passing over sprocket 44 loosely mounted on shaft 28 but adapted to be connected to rotate shaft 28 by -clutch member 45. As so far described, the parts, except the parts 11, 12, 13 and 14, are well known and their operation Well understood, that is, assuming the shafts 10 and 15 to be one shaft. However, in carrying out my invention in the form described, I provide two shafts 10 and 15 and I secure to the end of shaft 10, the discmember 11 carrying the cylinders 12 in which are pistons operated by piston rods 13 connected to the crank arm 14 secured on the shaft 15. If it be assumed that the shaft 15 be held stationary and the disc 11 be rotated b the prime mover, the pistons in the cylin ers 12 will be operated back and forth and so caused to compress air therein, which air is drawn from the surrounding atmosphere in any suitable manner and the compressed air is forced out of the cylinders into a passageway 46 lin the disc 11 and from the passageway 46 into a passageway 47 extending through the shaft 10, which passageway 47vconnects with a pipe 48 extending into a stationary stufling box 49 connected with a safety or relief valve 50. 51 represents a suitable pressure gauge for indicating the air pressure built up by the action of the pistons in the cylinders 12. The air.

under pressure from the pipe 48 passes freely to the pipe 52 andto a reducing valve 53 and from the reducing valve 53 a pipe 54 leads to an engine or air motor 55 which when sufficient pressure has been built-up in the pipe 54 causes operation of the engine or air motor 55 so that it will rotate the gear 56 which in -turn rotates the gear 57 secured onthe shaft 28, and so will rotate the drum 3() and operate upon the cable 31 to raise o r tend to raise the rotarv drilling tool or member.

It will be seen, however, that when the engine or prime mover 6 is started and there being some resistance to the rotation of the drillingtool 26 and, therefore, some resistance to the turning of shaft 15, the shaft 15 will remain stationary for a certain time until a certain pressure has been built up within the passageways 46, 47, etc. by operation of the pistons in the cylinders 12. This pressure, however, soon builds up to a point where it acts to prevent the pistons from operating in thecylinders l2 and rotation of the disc member 11 causes operation of the shaft 15 through the crank 14 and so, through sprocket 18, sprocket chain 20 andsprocket 21 and shaft 22, causes the table 24 to rotate the drilling tool. As the drilling tool encounters more resistance in its work a higher pressure is automatically built up by the pistons in the cylinders 12 in order to cause a continued rotation and operation of the drilling member. Should, however, thel resistance offered the drilling tool or member be so great as to be likely to twist off or break the drilling member or otherwise injure the apparatus, the pressure built up by the pistons in the cylinders 12 will reach such a. value that it will cause a pressure to be applied to the engine 55 through the pipe 54 sufiicient to cause this engine to act on the drum 30 and tend to raise the drilling tool which is fed into its work by the action of gravity and so decrease of thel feed of the tool responsive to such lincreases in the resistance offered the tool in rotation and thus decrease the resistance offered the tool against rotation, thereby resulting in a uniform operation lof the drilling tool and preventing injury or damage to the drilling member or other parts ofthe apparatus.' If for any reason this built up pressure should not be effective in relieving the load on the drill, the pressure built up is limited by the safety valve 50 which is set for a certain maximum pressure which permits the air thus built up under pressure to'escape to the outside atmosphere, thereby limiting the force which may be applied to rotate the drilling tool or member. This pressure may be so chosen that even with the drilling tool held stationary `in its Work (as in case it should in some way become caught) the force applied in tending to rotate the tool will not be sufficient to twist it off or injure the same. In such case the shaft 15 will'be'held stationary but the shaft 10 and Ydisc 11' will continue to be rotated by the prime mover 6 and the pistons in the cylinders 12 will continue to operate, the air being thus built up under pressure escaping through the safety valve 50 to the outside atmosphere. The reducingvalve 53 may be of any suitable or well known type but is preferably one which reduces the pressure to a given percentage of ythe pressure applied thereto. That is, the pressure permitted thereby in the pipe 54 will be a given percentage or proportion of the pressure ofthe air supplied thereto through the pipe 52. Thus during normal operation the engine or air motor 55 will act to continuously tend to raise the drilling tool or member against the action of gravity, the force so applied in opposition to gravity being responsive to and more or less proportional to the variation ofv is not suiciently decreased by partially re lieving the pressure of'gravity on the tool, the pressure may continue to be built up by the pistons in. the cylinders 12 to such a point that the air motor 55 will actually cause the drilling tool to be raised against the action of gravity and so relieved of its Work until it may again be rotated in anormal manner. When it is desired to raise the drilling tool or member entirely, this may be done directly from the shaft '10 by throwing in one or the other of the clutches 41 or 45.

`^ added to the drilling tool as the hole is drilled deeper, the setting of the reduction valve 53 may be altered or adj ustedso as to produce-a greater pressure in the pipe 54 with respect.'

to the pressure in the pipe 52 and so compensate for the added weight and corre' spending added effect of gravity on the drill ing tool as. the length and. weight of the drilling tool is increased. 'Also the safety orre-V lief valve 50 may be adjusted 4for any desired maximum pressure depending upon the size of the drilling tool and other conditions. But by adjusting the reduction valve 53 in any suitable manner as byK- turning the nut 60 in a manner Well understood by those skilled in the art so as to' adjust the force supplied by the engine or airmotor 55 to'correspond with the size, length and Weight of drilling member, the drilling member will be fed into its Work with a given uniform force except that shouldv it encounter increased resistance to rotation, the feed thereof will be controlled so as to decrease the resistance to its rotation, thus limiting the torque which is applied t-o rotate the tool and this in accordance with different conditions, but in any case so that the maximum torque applied to the tool will be less than that which will twist apart the tool or do other serious injury. Should the' resistance offered the tool be soigreat that the shaft 15 slows down or stops While the shaft '10 is cntinually driven by the prime mover 6, the pressure built up in the cylinders 12 will become so great that the engine or air motor 55 will actually Withdraw the drilling member from its Work or if the engine 55 fails to operate in this manner, the pressure built up will be limited by the safety lvalve 50 and so prevent the force applied to the tool from becoming so great as to prevent substantial injury. When the engine or motor 55 acts to 7..) apply greater force tending' to rotate the drum 3Q against the action of gravity due to the weight of the drillingmember or when the drum 30 is actually rotated so as to raise A the drilling tool, the pressure with which the 8U drilling tool is applied to its Work will be decreased orvrelieved thereby allowing the drilling tool to again freely revolve so that the pressure built up in the cylinders 12 will drop and continue to drop until it reaches 85 such a point that it balances the load encountered by the drilling member and this decrease in pressure acts to decrease the force applied by the engine or motor 55 tending to raise the drilling tool so that gravity a ain au operates to feed the drilling tool towar itswork and the drilling'tool is thus automatically again fed to its work in away consistent with maximum efficiency. In the arrangement shown this is accomplished by the U5 varying pressure produced in the cylinders -12 by relative rotation of the shafts 10 and 15. This pressure is indicated by the ,L fauge 51 andby observing the gauge the operator can tell at all times the relative amount of -luu Work being done by the drilling tool.

Referring to the modification shown in Figs. 3; 4 and 5 the same drum for raising `and lowering the drill is shown at 30, on the shaft 28 having bea-rings at 29. Theshaft W5 28'has' sprocketsfjflO and 44 loosely mounted thereon but adapted te be connected to rotate the shaft'28 by sliding clutch members 41 and 45 respectively. The sprocket-s4() and 44 are driven by sprocket chains from sprocket-s- H" 88 and 42 respectively fixed on'the main drivi ing shaft llhaving bearings at 16. The driving shaft is'similar to the driving shaft 10 of Fig. 1 except that the former has no passage therethrough. The driving shaft 10 is driven n by any suitable engine or prime mover through sprocket 9.

The driven shaft 15 having bearings at 17 has a sprocket' 18 loosely mounted thereon but which may be connected to be driven by "i" the shaft 15 by a sliding clutch member 19. The sprocket 18 is connected to rotate the table which rotates the .drill as shown in Fig. 1.

Rigiflly securedA on the' end of'the shaft`i15 hii 'is a disc 61, provided with"parallel guideways (S2 along which a casing 63 is adapted to slide. f -The casing 63 mav be moved along the guide- Ways by means of-a screw 64 cooperating with nu a bracket 65 rigid with the disc'61. The casing 63 contains` a fluid pressure pump comprising a casing 66 see Fig. 5) having, 1n the particular form s own, seven c'ylindrlcal vbores in which operate seven pistons 67 respectively. The pistons 67 are pivoted at their outer ends to a ring member 68 rotatable in a corresponding circular aperture in the casing 63. The cylinder casting 66 is provided with a central aperture in which the end of the shaft 15 extends and the casting 66 is rigidly connected to the shaft 10 to be rotated thereby. The shaft 15 has two segments cut therefrom at 69`and 70 directly opposite the pistons 67 and the shaft 15 is provided with longitudinal passages-71 and 72 communicating respeetlvely with the spaces 69 and 70..-The shafts 10 and 15 are journalled about the same axis but the casing 63 is adjusted by the screw 64 so that the center of the ring 68 iseccentric thereto as shown in Fig. 5. If, with such an arrangement the shaft lbe held relativel stationary and the passage 71 be connecter? to an oil or other fluid supply and the casting 66 be rotated by the shaft 10 relatively to the shaft 15, the pistons and their cylinders will be rotated with respect to shaft 15 and segment spaces 69 and 7 0, thereby causing the pistons to operate back and forth in the1r respective cylinders and draw in oil or other fluid through the passage 71 and force the same out through passage 72. The construction and mode of operation of such a fluid pump is well known so that further description thereof is unnecessary.

lhe outer end of the shaft 15 is extended into a stationary stuffing' box 73 wherein suitable connection ismade between the outlet passage 72 and a pipe connection 74, the passage 72 always communicating with the latter, even `when the shaft 15 is rotating with respect thereto. The vipe 74 is provided with a pressure gauge 79 or indicating the pressure of the oil or other fluid in the pipe 74. Communicating with the inlet passage 71 is ,apipe section screwed into theend of shaft l5 as shown 1n Fig.`4 andlthis pipe section 75 extends into a stuffing box 76 on a pipe 77 leading to an oil supply tank 78 or other fluid supply.

The pipe 74 leads to a safety or pressure relief valve 80. yIf the pressure of the fluid in pipe 74 exceeds the predetermined value fonwhich the valve is set, which value may be adjusted from time to time as desired the relief valve will permit the escape of fluid therefrom into the pipe 81 .whence it flows 4back into the supply tank 78, and-so prevent the pressure in the pipe 74 from exceedingV the predetermined value for which,v the valve is set. The pipe 74 is always in open communication with a pipe 82 so that the fluid is forced under pressure from pipe 74 into pipe 82 and the pressure of the fluid inv pipe 82 will always be the'same as the pressure of the fluid in pipe 74. The pipe 82 leads to a 84. The pipe 84 leads to the intake'of a fluld` or hydraulic motor 85 of any well known or suitable kind. If desired the motor 85 may be of the type shown in -my copending application Ser. No. 151,306 filed Nov. 29, 1926. The spent or exhaust fluid from the motor is conducted by a pipe 86 back to the fluid supply tank 78. I preferably employ a fluid motor 85 having means such as a shaft'at 87 which may be turned to vary the stroke of the motor so that the torque exerted by the motor may be varied with any given pressure of the opera-ting fluid supplied to the motor. The motor 85, when operated by the fluid under pressure from the pipe 84, operates on the gear 88 which meshes with the gear 57 and so acts on the drum 30 as described in connection with Figs. 1 and 2.

The function and mode of operation of the apparatus illustrated in Figs. 3, 4 and 5 is substantially the same as that of Figs. 1 and 2 except that instead of operating with air pressure it is designed to operate with liquid, such as oil, under pressure. Thus the Idrill or work member is driven by `shaft 15 and the lo'ad thereon will cause the shaft 15 to lag behind the driving shaft 10 until the hydraulic pump in casing 63 builds up a fluid pressure in pipes-7 4, 82, etc., sufficient to cause the shaft 15 to be driven at the desired speed under normal conditions. If the load on the shaft 15 becomes excessive there will be a further rotation of lthe shaft 10 relative to the shaft 15 causing a reaterpressure to be built.y up in the pipes 4, 82 and 84 and so causing the fluid motor 85 to exert a greater torque tending to lift the drill Iagainst the action of gravity and so decrease the load on the shaft 15. If the load on the shaft 15 should increase to much 'greater value,l the pressure may increase'to'such a value Ias to.

cause the motor85 to actually raise the drill and if this should not decrease the load on the drill the safety or relief valve will permit the escape of fluid back to the tank 78 and so hmit the force which will be applied to the drill to a. value which will not prove injurious. The torque applied by the fluid motor to the drum 30 for any given pressure in pipe 84, may be variedl and adjusted independently of thepower applied to operate the motor while the motor is in operation, by adjusting shaft 87 so as to'change the stroke of the motor so that when the size of the -drilling tool is increased or the length of the tool is'increased'as the well is drilled deeper, sufficient torque may be applied to the drum`30 to compensate for such increascs in the weight of the tool. This torque may also be varied'to adjust the pressure with which the tool is fed into its work to meet different conditions in the work. Likewise the torque exerted by the shaft may be varied and the pressure produced inv the 5 pipesi'74, 82 and 84 for any given load on the tool maybe varied for similar purposes, by adjusting the screw 64. Any suitable arrangement may be provided for adj ustinv the screw 64 while the disc 6l is rot-ating and the `apparatus is in operation.

' The various parts in the various drawings are not all drawn'to the same .scale and the drawings are in many respects merely diagrammatical in order that the invention may be morelclearly illustrated.

While I have described my improvements in connection with drilling apparatus and more particularlyin connection with oil well drilling apparatus, it will be obvious that many ,changes and modifications may be made and the invention embodied in widely different forms and kinds of apparatus, without departing from the spirit and scope of the invention in its broader aspects. Thus the invention in its broader aspects may be embodied in any kind of apparatus Where it is desirous of limiting the torque or force impressed upon tool, shaft or other work member, and particularly where it is desired to regulate or control the feed of a tool or its work, either relative tothe other, and in either direction, responsive to variations in the resistance olered the tool or the load applied to the member. B adjusting the reducin valves 53 and 83 or different values,

or a opting different kinds of reducing valves, the control or regulation of the feed responsive to the load variations may be widely varied as desired.

In oil well drilling apparatus such as is frequently employed the cutting tool or drilling element is quite heavy and may vary. in weight from 300 lbs. to possibly 300,000 lbs. depending on the size and depth of well or hole that is being drilled. Thus when the hole reaches a considerable depth the weight of the various sections of the rotating drilling element becomes very great and the power required to rotate the drilling element, if this weight is not largely relieved, will be very great, and more than suflicient to twist the tool'apart, .with resultant great damage and in some cases necessitating an abandonment of the well being drilled. But by the use of my invention 1n its preferred form a varying force or torque is automatically applied to the hoisting drum 30 so as to .largely relieve this weight and control the feed of the tool in such a manner that the power required to rotate the tool at the normal rate will be maintained nearl constant so that the drilling is aceomplishe in a most speedy and eicient manner, and should con.

ditions occur which prevent the rotation of the tool the torque applied is limited by the operation of the prime mover builds up a Huid pressure, means whereby said fluid pressure acts to rotate the drillin a force proportional to said uid pressure,

=and means acting to decrease the force acting to feed said member` with respectv to its work responsive to variatlons in said Huid pressure. 2. The combination of a rotary drilling member, a prime mover, means whereby operation of the prime mover builds a fluid pressure, meansv whereby said fluid pressure acts to rotate the drilling member and means whereby the feeding of the drilling member with respect to its work is controlled responsive to variations in said :Huid pressure.

3. The combination of a rotary drilling member, a prime mover, means whereby operation of the primer mover builds up a Huid pressure, means whereby said fluid pressure acts to rotate the drilling member and means whereby the feeding of the drilling member with respect to its work is controlled responsive to variations in said Huid pressure, and means independent of the prime mover for limiting said fluid pressure. c 4. The combination of a rotary work member adapted to encounter a variable resistance in its work, a prlme mover, meanswhereby operatlon of t e prlme mover'builds up 4a fluid pressure, means whereby said Huid member by pressure acts to rotate the work member and means whereby the feeding of the work member relative to its work is vcontrolled responsive to variations in said fluid pressure. 5. The combination'of a rotary work member adapted to encounter a variable resistance in its Work, a prime mover, connections between the prime mover and the rotary work member whereby the prime mover may rotate the work member, said connections including iiuid pressure generating means actingv to build up a fluid pressure dependent upon the resistance encountered by the work member in its work, and means permitting escape of the Huid under pressure when a predetermined pressure has been reached. Y

6. The combination of a rotarywork member adapted to encounter a variable resistance in its Work, a prime mover, connections between the prime mover and the rotary work member whereby the prime mover may rotate the work member, said connections including member, said connections including a fluid` fluid pressure generating means acting 'to build up a fluid pressure dependent upon the resistance encounteredby the work member i-n its work, and means whereby the feeding of the work member with respect to its work is controlled responsive to variations in said.

fluid pressure.

7 The combination of a rotary work member adapted to encounter a variable resistance in its work, a prime mover, connections between the prime mover and the rotary work member whereby the prime mover may ro- -ftate the work member, said connections nvcluding fluid pressure` generating means acting to build up a fluid pressure dependent upon the resistance encountered by the .work member in its. work, and means whereby the feeding of the work member` in its work is controlled responsive to variations in said fluid pressure, and means limiting the pressure of the fluid by permitting the escape thereof when a predetermined pressure has been reached.

8. The combination of a rotary drill member, a prime mover, connections between the prime mover and the rotary drill Amember whereby the prime mover may rotate the drill pressure generator acting to build up a fluid pressure in accordance with the load encountered by the drill member, and means substantially limiting said fluid pressure to a predetermined value to limit the forcelwhich the prime movermay apply to rotate thev into its work.

10. The combination of a rotary drill member fed by gravity toits work,ia shaft connected to drive said drill member, a prime mover, a shaft driven thereby, fluid pressure generator means connecting said shafts and acting to build up a fluid pressure in accordance with the load encountered bythe drill member, and means whereby said-fluid pressurey acts to oppose the force of gravity in feeding the drill member to its work.

11. The combination of a rotarydrill member fed by gravityto its work, a shaft connected to drive said drill member a prime mover, a shaft driven thereby, flui' pressure generator means connecting said shafts and acting to build up a fluid pressure in-` accordance with'the load encountered by the drill member,'and means whereby said fluid lpressure'acts to oppose the force of gravity in ator connecting said shafts whereby the first feeding the drill member to its work, and means permitting the escape of said fluid under pressure when a predetermined pressure has been reached to limit the force which may be applied to rotate the drill member.

12. The combinationof a rotating shaft, a shaft adapted to be rotated thereby, means` including a fluid pressure generator connecting said shafts and acting to build up a fluid pressure in accordance with the load encountered by the driven shaft, and means whereby variations in said fluid pressure tend to decrease the load encountered byv said driven shaft.

13. The combination of a rotating shaft, a shaft adapted to be rotated thereby, means connecting said shafts and acting to build up a fluid pressure in accordance with the load encountered by the driven shaft, and means permitting the escape of the fluid under pressure when a predetermined pressure has been reached, to limit the force which the first shaft will'apply to the driven shaft.

14. The combination of a rotary table, a drill member slidable therethrough and rotated thereby, a prime mover, a shaft rotated by the prime mover, a second shaft, means connecting said shafts including a fluid pressure generator whereby thel first shaft is adapted to drive the second shaft and build up a fluid pressure varying with the load encountered by the second shaft, means whereby the-second shaft rotates said table to rotate said drill member, said drill member bein fed to its work by gravity, and means for ecreasing the force with which said drill member is fed to its work in accordance with certain variations in said fluid pressure.

15. The combination of a rotary table, a drill member slidable therethrough and rotated thereby, a prime mover, a shaft rotated by the rime mover, a second shaft, means i connectlng said shafts whereby the first shaft is adapted to drive the second shaft and build up a fluid pressure varying" with the load encountered by the second shaft, means whereby the second shaft rotates said table to rotate said drill member, said'drill member'being fed toits work by gravity, and means permitting the escape of the fluid under pressure when a predetermined pressure has been reached, to limit the force which the first shaft will apply to the driven shaft.`

. 16. The combinatlon of a rotary table, a 120 drill member slidable therethrough and rotated thereby, a prime mover, a shaft rotated by the prime mover,`a second shaft, means lnclusive of a fluid pressure genershaft is adapted to/drive the second shaft and build up a fluid pressure'varying with the load encountered by the second shaft,. means whereby the second shaft rotates said table to rotate said drill member, said drill .130*

member being fed to its work by gravity, and

means permitting the escape of the fluid under pressure when a predetermined pressure has been reached, to limit the force which the iirst shaft will apply to the driven shaft, and means whereby certain increases in said fluid pressure act 'to decrease the force with which said drill member -is fed to its work.

17. The combination of a work member adapted to encounter a variable resistance in its work, a prime mover, connections between the prime mover and the rotary Work member whereby the prime mover may rotate the work member, said connections embodying fluid pressure generator means acting to build up a fluid pressure dependent upon the resistance encountered by the Work member in its worlgmeans forregulating the feed of the Work member with respect to its work, a fluid motor controlling said last mentioned means, and connections from said fluid under pressure to said fluid motor where- -by the Huid motor is operatedby said fluid under pressure. s

18. The combination of a Work member adapted to encounter a variable resistance in its work, a prime mover, connections between the prime mover and the rotary work member whereby the prime mover may rotate the work member, said connections embodying fluid pressure generating means acting tol build up a fluid pressure dependent upon the resistance encountered by the Work member in its work, means for regulatingr the ieed of the work member with respect to its work, a iluid'motor controlling said last mentionedvmeans, and connections from said fluid under pressure to said fluid motor Whereby the fluid motor is operated by said fluid under pressure, andan adjustable reduction valve in said last mentioned connections.

19. The combination of a Work member adapted to encounter a variable resistance in' its work, a prime mover, connections between the prime mover and the Work member Whereby the-prime mover operates the Work member, said connections including a fluid pump acting to build up a vfluid pressure dependent upon the resistance encountered by the Work member, and means for adjusting the stroke of said pump to vary the said fluid pressure independently of the resistance encountered by the Work member and means for regulating the feed of the Work member with re'- spect to its work responsive to variations in said Huid pressure.

20. The combination4 of a rotary cutting member, a driving shaft, a hydraulic pump connected to be driven by said shaft, a shaft l driven by thehydraulic pressure built up by said pump and connections whereby the lust mentioned shaft drives the cutting member, and means whereby increases in said hydraulic pressure tend to decrease the load encountered by the cutting member.

21. The combination of a rotary drill device, a prime mover, transmission means connecting the prime mover and drill device, said transmission means including two rotatable elements adapted to rotate with respect to each other, and a fluid pressure generator connecting said elements, and means whereby the feed of 4the drill is controlled by the slip between the elements.

In testimony whereof I have signed my name to this specification.

LOUIS H. THULLEN. 

